Plasma arc torches are widely used in the cutting and marking of materials. A plasma torch generally includes an electrode and a nozzle having a central exit orifice mounted within a torch body, electrical connections, passages for cooling, and passages for arc control fluids (e.g., plasma gas). The torch produces a plasma arc, a constricted ionized jet of a gas with high temperature and high momentum. Gases used in the torch can be non-reactive (e.g., argon or nitrogen) or reactive (e.g., oxygen or air). During operation, a pilot arc is first generated between the electrode (cathode) and the nozzle (anode). Generation of the pilot arc can be by means of a high frequency, high voltage signal coupled to a DC power supply and the torch or by means of any of a variety of contact starting methods.
Known power circuits and associated cooling systems for plasma cutting systems require numerous hardware components. For example, existing power circuits include four insulated gate bipolar transistors (IGBTs); eight direct current (DC) bus capacitors; six power resistors; four fans; two heat sinks; two DC bus capacitor support plates; and/or four printed circuit board (PCB) assemblies. These known technologies introduce significant bulk and/or complexity into the power supply design in terms of the power supplied per unit mass, the power supplied per unit volume, and/or a temperature of the power supply during operation.